Tote for conveyor

ABSTRACT

A tote for a conveyor system may include an upper part and a lower part. The upper part may define an upper, article-supporting surface. The article-supporting surface may be adapted to receive and support articles while the articles are conveyed in or on the tote. The lower part may define a lower, substantially plane bearing surface that extends over an area substantially equal to the article-supporting surface. The upper and lower parts may be transparent to X-rays. The upper and lower parts may be made from fire-retardant material. A plurality of support points and areas may be provided between the upper part and the lower part in order to transfer forces between the article-supporting surface and the bearing surface.

The present application is a division of U.S. patent application Ser.No. 10/491,105, filed on Sep. 1, 2004, now U.S. Pat. No. 7,318,519 (as anational stage entry of PCT Application PCT/DK02/00642, filed on Sep.27, 2002), and claims priority from Denmark Patent Application No. PA2001 01412, filed on Sep. 27, 2001, the contents of both of which areincorporated herein by reference.

The present invention relates to a tote for a conveyor system in whichthe articles are conveyed in totes.

BACKGROUND

It is known to transport articles, in particular baggage, on conveyorsystems in which the articles are situated in trays, boxes or totes, inorder to treat the articles more careful and prevent damages on and wearof the articles and interruption of the operation of to the conveyorsystem caused by pendent parts of the articles, such as belts. The totesmay be separated from the conveyor line, cf. EP-A-0 456 297, EP-A-0 742163 and U.S. Pat. No. 5,301,790, to store the articles temporarilytogether with the tote.

The totes generally consist of two parts, a first part that supports thearticle to be transported, such as a tray having a concave surface asshown e.g. in U.S. Pat. No. 5,301,790, which prevents the article fromsliding off the tote and facilitates the discharge of the article bytilting of the tray, and a second part to support the first part as wellas transferring the driving force from the conveyor line to it andthereby to the article. Thus, the second part is exposed to heavy wearfrom the contact with the drive means of the conveyor and shouldtherefore be manufactured from a wear-resistant material. For one of theknown types, the second part is designed to engage dedicated conveyorand drive means and the wear-resistant material may be a glass-fibrereinforced plastics material, as disclosed in EP-A-0 581 398, or may bemetal as disclosed in WO 01/05685. Another known type is therotationally moulded tote having a hollow interior and a flat lowersurface that support the tote on tilt trays, such as disclosed in U.S.Pat. No. 5,301,790, on belt drives, chutes, etc. The wear-resistance ofmaterials that are suitable for rotational moulding is low but in so faras the totes are used solely on tilt trays, the wear-resistanceproperties of the rotationally moulded tote may suffice. The shape isadvantageous because the totes may be transported on a multitude ofdifferent types of conveyors, but for use at conveyors with belt drivesetc. in which the totes are driven directly, the wear-resistance of thematerial is insufficient and the lower surface of the rotationallymoulded tote has to be reinforced by a sheet of a wear-resistantmaterial, typically a steel sheet.

It is furthermore a known demand to conveyor systems that the articlestransported thereon may be subjected to x-ray analysis, e.g. for qualityinspection in production lines, but more commonly for security controlof baggage for content of explosives, etc. To ensure the quality of thex-ray inspection which is performed with a vertical ray direction, it isrequired that material situated between the x-ray source and the x-raydetector is fairly transparent to x-rays and that the damping of theintersecting x-rays is substantially uniform throughout the inspectedarea perpendicular to the ray direction. As the known totes does notfulfil these requirements, mainly due to the presence of metal sheets orglass fibres, which both prevent the use of x-rays, the articles may inknown systems be x-rayed before they are loaded onto the totes, thearticles may be unloaded from the totes before the x-ray analysis andsubsequently re-loaded onto the totes, or the totes may be separated inthe first part carrying the article and the second metal part prior tothe x-ray analysis, followed by a reunion of the two parts afterwards asdisclosed in WO 01/05685. The tote manufactured by rotational mouldingis in itself suitable for carrying articles for x-ray analysis but thematerial used for reinforcement of the lower surface severely reducesthe x-ray transparency of the tote thus renders the tote unsuited forcarrying articles during x-ray analysis thereof.

BRIEF DESCRIPTION OF THE INVENTION

The above-defined problem is according to the present invention solvedby providing a tote for a conveyor system comprising

an upper part defining an upper, article-supporting surface being ofconcave cross-section, and

a lower part defining a lower, substantially plane bearing surface thatextends an area substantially equal to the article-supporting surface,

the upper part and the lower part being non-opaque i.e. transparent tox-rays, wherein the lower part is injection moulded from a plasticsmaterial, the plastics material being preferably wear resistant.

Accordingly, the invention provides a conveyor system which facilitatesthe x-ray analysis of the articles transported on a conveyor systemutilising totes. The tote is preferably made from two parts that areassembled to form a hollow structure. At least the second, lower partmay be injection moulded. It has been found to be advantageous to employinjection moulded parts, as injection moulding allows for the use ofwear-resistant materials that render the reinforcement of the lowersurface superfluous. Thereby, the tote may be made to be fairlytransparent to x-rays and thus permit x-ray analysis of articles whilebeing transported on the totes as opposed to the known, rotationallymoulded and metal sheet reinforced totes and to the known totes withdetachable lower parts.

The bearing surface may have openings defined in it as shown anddiscussed below without being outside the scope of the presentinvention. It is preferred that the bearing surface has substantiallythe same extent as the article-supporting surface, thus providing forthe use of the tote on various types of conveyors as opposed to thepreviously discussed totes that are designed for conveyors dedicatedonly to that type of totes.

It is preferred that the x-ray transparency of the tote perpendicularlyto the bearing surface is substantially homogeneous throughoutsubstantially all of the tote so as to minimise the disturbances of anx-ray analysis of an article situated on the article-supporting surfaceof the tote. This is in a preferred embodiment obtained by designing andmanufacturing the tote so that the total thickness of the material ofthe upper part and the lower part of the tote perpendicularly to thebearing surface is substantially homogeneous throughout substantiallyall of the tote. The total thickness is defined as the sum of thematerial thickness of the upper part and the material thickness of thelower part of the tote.

Both the upper part and the lower part may preferably be injectionmoulded from a wear-resistant plastics material in a preferredembodiment of the invention because not only the bearing surface butalso other parts of the tote is subjected to wear, such as the sidewalls and end walls of the tote.

The preferred shape and type of the tote is one wherein the upper partand the lower part together form a substantially closed, hollow body.This construction, which is a kind of sandwich construction, is lightweight and strong and is thus advantageous to some of the previouslyknown totes, e.g. as disclosed in EP-A-0 581 398, in which the upperpart is supported by the lower part at a middle section only, for whichreason the upper part must be of a strong, self-supporting construction.

In a further preferred embodiment, the tote has outer sides extendingbetween the article-supporting surface and the bearing surface, whereinsaid outer sides have one or more bumpers manufactured from a materialof a higher wear-resistance than that of the lower part and preferablyalso of a lower surface friction coefficient, the bumpers extendingalong the outer sides covering at least part of the circumference of thetote. The bumpers protect the outer vertical sides of the tote, inparticular the corners from wear and prolong thus the life of the tote.

The material used for the trays may be, e.g., acrylonitrile butadienestyrene (ABS), polyamide (PA), polyethylene (PE), polypropylene (PP), ora mixture thereof, and/or admixed with suitable materials for enhancingthe wear resistance and/or for making the mixture fire-retardant. Ofthese, polyethylene has the best x-ray qualities.

In an example embodiment, the wear-resistant plastics material comprisespolycarbonate (PC) as well as acrylonitrile butadiene styrene (ABS).

A damping means may be included in the hollow structure, i.e. in acavity between the upper part and the lower part of the tote. This willsilence the conveyor system when operated. The damping means may be madeof e.g. foam rubber, preferably in a fire-retardant form.

BRIEF DESCRIPTION OF FIGURES

An embodiment of a tote according to the present invention is forillustration of the invention described below with reference to theaccompanying drawings of which

FIG. 1A shows a tote as seen from the side being parallel to the mostcommon direction of movement of the tote on a conveyor. FIG. 1B shows atote as seen from an end perpendicular to the direction of movement.FIG. 1C shows a tote as seen from above. FIG. 1D shows a perspectiveview of the tote. Outer measures (in millimeters) of the tote appear inFIGS. 1A and 1B. FIG. 1E displays a cross-section along A-A of FIG. 1C.

FIG. 2 is an enlarged perspective view of the tote as seen from aboveshowing the article-supporting surface,

FIG. 3 is a cross section of the tote along a line perpendicular to thedirection of movement,

FIG. 4 is a perspective view of the tote as seen from below showing thebearing surface,

FIG. 5 is a perspective view of the lower part of the tote as seen fromabove, showing the interior side of the lower part,

FIG. 6 is an enlarged detail of FIG. 5,

FIG. 7 is a perspective view of the upper part of the tote as seen frombelow,

FIG. 8 is an enlarged detail of FIG. 7,

FIG. 9 is an enlarged detail of FIG. 4 showing details of theprojections and slits used to gather the two parts of the tote,

FIG. 10 shows a detail of a corner of a tote equipped with a bumper,

FIG. 11, shows the lower part of an alternative embodiment of the toteas seen from above, showing the interior side of the lower part, and

FIG. 12 is a perspective view of the alternative embodiment of the toteas seen from below showing the bearing surface.

DETAILED DESCRIPTION OF THE EMBODIMENT

The embodiment of a tote 1 according to the invention as shown in theaccompanying drawings is comprised of an upper part 2 defining anarticle-supporting surface 3 and a lower part 4, supporting the upperpart 2 and defining a bearing surface 5 on which the tote 1 may beconveyed on multiple types of conveyors, including belt conveyors,roller conveyors and slides. The bearing surface 5 extends oversubstantially the same area as the article-supporting surface 3 so thatforces may be transferred between the two surfaces 3, 5 at a pluralityof support points and areas thus allowing a simple and slenderconstruction. The wide area of the bearing surface 5 permit the tote 1to be conveyed on multiple types of conveyors and the closed side walls6 and end walls 7 connecting the article-supporting surface 3 and thebearing surface 5 transfer forces between the two surfaces 3, 5 as wellas receive sideways impacts with the conveyors, in particular inconveyor sections that are curved in the horizontal plane in which theturning of the tote 1 is guided by vertical sides of the conveyorsections with which sides the totes 1 collides.

A damping device 23 (as shown in FIG. 1E) may be included in the hollowstructure, e.g., in a cavity between an upper part and a lower part ofthe tote 1. The damping device 23 may silence the conveyor system whenoperated. The damping device 23 may be made of, for example, foamrubber, preferably in a fire-retardant form.

The cross-section of the tote 1 perpendicular to the direction ofmovement, i.e., parallel to the end walls 7, is shown in FIG. 3. Theconcave shape of the article-supporting surface 3 consists of a middlesection 8 with a low concavity, i.e., a long radius of curvature, twointermediate sections 9 with a high concavity, and two straight sections10. The transition between sections 8, 9, and 10 is smooth so thetangent to the surface 3 is continuous along the cross-section and thefriction of the surface 3 is low. Thereby, it is obtained that thearticles remain in the tote 1 during conveying due to the height of theside walls 6 and the flatness of the middle section 8, whereasintroduction of articles into the tote 1 and, in particular, dischargeof articles from the tote 1 by tilting is facilitated by the curvatureof the surface 3.

The tote 1 is shown as seen from below in FIG. 4, from which the extentof the bearing surface 5 being substantially equal to the area of thearticle-supporting surface 3 is clearly seen. The bearing surface 5 maybe provided with twelve hollow columns 11 that extend from the upperside of the lower part 4, leaving openings in the bearing surface 5. Thecolumns 11 are formed as the frustum of a cone, as shown in FIGS. 5 and6, and the upper end 12 of the columns 11 engages with complimentaryopenings 13 in the lower surface 14 of the upper part 2, as shown inFIG. 7. The columns 11 fulfill, together with the side walls 6 and endwalls 7, the function of supporting the upper part 2 of the tote 1 andthereby the article situated on the article-supporting surface 3. Theclose support of the upper part 2 from the lower part 4 allows for aslender and simple construction of the tote 1. Such close support couldalternatively be achieved by a plurality of parallel ridges extendingfrom the lower part 4 to the support of the upper part 2. The columns 11are hollow because a sufficient compression strength is provided therebyand because an area of low transparency to x-rays is avoided, as wouldbe the result of a massive column 11.

A compartment 15 for holding a machine-readable identification unit,such as a RFID tag (radio frequency identification device tag), isprovided in the lower part 4, as show in FIG. 6.

The upper part 2 is shown from below in FIG. 7, in which the structureof the side walls 6 and end walls 7 as sandwich constructions is shown,including an inner wall 16 and transverse ribs 17 connecting the innerwall 16 and the side walls 6 and the end walls 7, respectively. Thereby,a light weight as well as strong construction is obtained.

FIG. 8 shows that the lower edge 18 of the inner wall 16 of the upperpart 2 is equipped with a plurality of equidistant projections 19 thatare formed to engage with corresponding slits 20 in the lower part 4,see FIGS. 5 and 6, and the projections 19 and the slits 20 are rivetedtogether as shown in FIG. 9. Alternatively, the projections 19 and theslits 20 may be clicked together, using latch-formed projections, weldedor glued together.

The upper part 2 and the lower part 4 of the tote 1 are designed so thatthe total material thickness between the article-supporting surface 3and the bearing surface 5 in the direction perpendicular to the bearingsurface 5 is substantially homogeneous throughout the tote 1 whereby itis obtained that the x-ray transparency of the tote perpendicularly tothe bearing surface 5 is substantially homogeneous throughoutsubstantially all of the tote 1. Thus, the disturbances of an x-rayanalysis of an article situated on the article-supporting surface 3 ofthe tote 1 are minimised.

The wear on the tote 1 is in preferred configuration of the conveyorsystem most intensive on the side walls 6 and end walls 7, and inparticular on the corners 21 where the two meet. The tote 1 is thereforein a further preferred embodiment provided with bumpers 22 manufacturedfrom a material of a higher wear-resistance than that of the remainingtote 1 as shown in FIG. 10. Thus, the life of a tote 1 before recyclingmay be substantially prolonged by the application of bumpers 22.

An alternative embodiment of the tote 1 is shown as seen from below inFIG. 12. The bearing surface 5 is provided with fourteen different sizedhollow columns 11 that extend from the upper side of the lower part 4leaving openings in the bearing surface 5. The columns 11 are formed asthe frustum of a cone as shown in a plan view in FIG. 11. Theprojections 19 and the slits 20, which are rivet together, are alsoshown in FIGS. 11 and 12. Alternatively, the projections 19 and theslits 20 may be clicked together, using latch-formed projections, weldedor glued together.

1. A tote for a conveyor system, comprising: an upper part; and a lowerpart; wherein the upper part defines an upper, article-supportingsurface, wherein the article-supporting surface is adapted to receiveand support articles while the articles are conveyed in or on the tote,wherein the lower part defines a lower, substantially plane bearingsurface that extends over an area substantially equal to thearticle-supporting surface, wherein the upper part is transparent toX-rays, wherein the lower part is transparent to X-rays, wherein theupper part and the lower part are made from fire-retardant material,wherein a plurality of support points and areas are provided between theupper part and the lower part in order to transfer forces between thearticle-supporting surface and the bearing surface, and wherein thearticle-supporting surface includes a concave cross-section.
 2. The toteof claim 1, wherein the lower part is injection molded fromwear-resistant plastics material.
 3. The tote of claim 2, wherein thewear-resistant plastics material comprises: polycarbonate (PC); andacrylonitrile butadiene styrene (ABS).
 4. The tote of claim 1, whereinthe upper part is injection molded from a wear-resistant plasticsmaterial.
 5. The tote of claim 4, wherein the wear-resistant plasticsmaterial comprises: polycarbonate (PC); and acrylonitrile butadienestyrene (ABS).
 6. The tote of claim 1, wherein the upper part is madefrom or made using one or more of acrylonitrile butadiene styrene (ABS),polyamide (PA), polyethylene (PE), and polypropylene (PP).
 7. The toteof claim 1, wherein the lower part is made from or made using one ormore of acrylonitrile butadiene styrene (ABS), polyamide (PA),polyethylene (PE), and polypropylene (PP).
 8. The tote of claim 1,wherein an x-ray transparency of the tote, perpendicular to the bearingsurface, is substantially homogeneous throughout substantially all ofthe tote.
 9. The tote of claim 1, wherein a total thickness of materialof the upper part and the lower part of the tote, perpendicular to thebearing surface, is substantially homogeneous throughout substantiallyall of the tote.
 10. The tote of claim 1, wherein the upper part and thelower part together form a substantially closed, hollow body.
 11. Thetote of claim 10, wherein foam rubber is included in the substantiallyclosed, hollow body.
 12. The tote of claim 11, wherein the foam rubberis in fire-retardant form.
 13. The tote of claim 1, further comprising:outer sides; wherein the outer sides extend between thearticle-supporting surface and the bearing surface, wherein the outersides include one or more bumpers, wherein the one or more bumpers aremade from material of higher wear-resistance than that of material ofthe lower part, wherein the one or more bumpers extend along the outersides, and wherein the one or more bumpers cover at least part of acircumference of the tote.
 14. The tote of claim 1, wherein the upperpart and the lower part are adapted to be riveted together, clickedtogether, welded together, or glued together.
 15. The tote of claim 1,further comprising: a compartment adapted to hold a machine-readableidentification unit.
 16. The tote of claim 15, wherein the compartmentis provided in the lower part.
 17. The tote of claim 15, wherein themachine-readable identification unit is a radio-frequency identificationdevice (RFID) tag.
 18. The tote of claim 1, further comprising: meansfor supporting the upper part; wherein the means for supporting theupper part rests on the lower part.
 19. The tote of claim 18, whereinthe means for supporting the upper part comprises: a plurality of hollowcolumns; wherein the columns extend from an upper side of the lowerpart, leaving openings in the bearing surface, wherein the columns areformed as frustums of a cone, wherein the tote further comprises:openings in a lower surface of the upper part; wherein the openings arecomplimentary with respective upper ends of the columns, and wherein theupper ends engage with the openings.